Apparatus for handling powdered fuel



Sept. 7 1926. 1,598,842

M. W. ARROWOOD APPARATUS FOR HANDLING POWDERED FUEL Original Fild MaI-Cb1.4-, .1923 2 sheets` sheet l u Il sept. 7 1926.

* -1,598,842 M. w. ARRowooD APPARATUS FOR HANDLING POWDERED FUEL originlFilm Maren 14, 1923 2 Sheets-Sheet 2 `als vPatented Sept. 7,1926.

UNITED STATES.

PATENT OFFICE.

i MILTON W. .ARROWOD, 0F WORCESTER, MASSACHUSETTS. l

`L rrfinana'rus non` HANDLING rownnnnn FUEL.

original apsnaation sled March 14, i923, serial Na". 624,927. Dividedand this application sled Januari le, 1924. serial No. 686,506.

i This invention relates to the handling of powdered coal and similarmaterial, thepresent application pending application,

-March 14, 1923.

In feedinggpowdered coal from hoppers and similar containers, there is atendency ifor the coal to pack and form 'an arch, which interferes withthe continuous feeding being a division of my Serial No. 624,927, filed10 operation. One of the purposes of my present invention is to preventthis arching and facilitate the uniform feeding of the coal. The coal inextremely linely powdered conf dition has a tendency to work into thebearings of the movable parts4 of the apparatus with the result thatthey customarily wear rapidly. Another object of this invention, is todispose the bearings for the movable parts of the apparatus outside thehousings in which the powdered coal is confined, s0 that the coal ispractically excluded from the bearings, and their life isy thereby muchprolonged. l

Another purpose of the invention is to provide novel gates. forregulating the delivery of powdered coal from the hopper to the mixingapparatus, which gates will prevent escape and leakage of the coalaround them, and also to provide means -for agitating the fuel tomaintain a uniform consistency and uniform weight per cubic unitthereof.

Other objects and advantages of this in- 'vention should be. readilyappreciated as thez same Abecomes better understood by reference to thefollowing description, when considered in" connection with the accom- Ipanying drawings.

Referring to the drawings: l

Fig. 1 is a vertical sectional view through an apparatus embodying myinvention;

Fig. 2' is a plan view partially in section of one end of the coalfeeding and preliminary mixing apparatus.. this ligure being 'taken onthe line 2 2 of Fig. 3;

Fig. 3 lis r a sectional view on ther line 3-3 of Fig. 2;`and

Fig. lis a fragmentary view of the mechanism for operating the controlgates shown in Figs. 2 and 3.

`Referring now to the drawings more in detail, reference character 5indicates generally the lower portion of a hopper in which the powderedcoal isstored and from which it is fed, this hopper being connected by aclosed joint with a tapered trough or recep- 55 tacle 6 into which thepowdered material falls by gravity from the hopper when the controlgates are open. The gates 7 and 8, which may be lof any preferred form,either curved or flat as shown', vare mounted on shafts 9 and 11,respectively, extendin through the walls of the hopper base an journaledin outboard bearings. Each shaftv is provided outside the hopper with anarm 12 which armsare connected by an operat- `ingl link 13.1,. It willbe manifest that by moving the link 13y longitudinally, rotativelmovements will be imparted to the shafts 9 and 1,1, to open and closethe gates. It will be observed from Fig. 3 that a stop ledge 14 isdisposed beneath the outer edge of gate 8 and a similar ledge 15 isdisposed over the outer edge of gate 7, whereby the movements of thesegates in lolle direction are limited. The inner edges of the gatesoverlap when in closed position so that when the gates are positionedasshown in full lines in Fig..2, the flow of material from the hopper iscompletely shut olf. By rotating the gates in a Iclockwise direction,viewing Fig. -3, they may be opened orpartially opened to Aany desireddegree, as indicated in dotted lines, to permit the requisite iow ofmaterial from the hopper. VTo insure a leak-tight fit, the margin ofeach gate is preferably provided with a feltsealingstrip 16, held inplace by ai retaining strip 17, which'holds the felt strip snuglyagainst the end walls of the passage.

y The tapered shape of the hopper induces a tendency of the coalv in thehopper to form an arch over the gate or gates so thatit will not feeduniformly.` This objectionable arch, however, may be obviated bysuspending within the hopper one or more heavy chains 18 which hang downto a point in proximity to the gate. The constant vibration of such achain or chains resulting from the operation of the machinery, preventsthe objectionable arching of the material in the hopper. 1

Beneath the gate -within the trough 6 and abovevthe bottom thereof,there is mounted a. rotatable shaft 19,7provided with radially extendingspokes or fingers 21, preferably inclined with respect to thelongitudinal axis --of said shaft and adapted upon rotation of the shaftto agitatel the material passing through the trough, thereby breakingany.

caked lumps or chunks therein and mixing the same so as to insure anuniformity 1n the consistency and specific gravity ofthe fuel, as Wellas facilitating'the feeding of` the-coal to the feed screw 22 disposedin the bottom of the trough. This feed screw is mounted upona shaft 23driven from any suitable source of power, and equipped with a gear 24which meshes with and drives a companion gear 25 on the shaft 19. Inorder ,to prevent leakage of the coal around the shafts and to precludeits entrance as much as possible into the bearings, theshaft 17 islmounted in outboard bearings 26 and 27,-

The other end of shaft 23 extends vthrough a shell 33 and is journaledin an outboard bearing 34, leakage at this end of the shaft beingprevented by a stuffing box 35. Within the shell 33 there is disposedaround the shaft a perforated cylinder 36, into which the coal isdelivered by the feed screw 22. Air under suitable pressure is deliveredto the interior of the cylinder 36 through a supply pipe 37, and thisair is mixed with the coal in the cylinder, the mixture being fur therfacilitated by the passage of the coal and air together outwardlythrough the perforations 1n the cylinder walls. From shell 33 themixture of coal and air isischarged througha neck 39 einto the mixerproper, or as it is commonly termed,-the burner,

This burner may be of Iany preferred construction but preferablycomprises, as shown for illustrative purposes, an outer cylindricalshell 41 in which are disposed a plurality or concentrically arrangedshells of progressively decreasing diameter, forming a series of fuelpassages alternating with air passages from which air delivered at theintake end 42 of the burner is delivered radially v into the mixingpassagesthrough apertures 43. The structural details of the burner willnot be further elaborated upon as they are fully described and claimedin the parent application previously mentioned.

In the operation of'my invention, the hopper gates 7 and 8 having beenopened the desired amount, the fuel inthe hopper which is prevented fromarching by the-chain 18, falls by gravity into the trough 6 where it isbroken up, Vagitated and mixed to a uniform conf Y perforated cylinder36. Here it is partiallyy mixed with air, delivered into the cylinder 3b'under pressure and upon being discharged outwardly through theperforations in this cylinder itbecomes further mixed as itis deliveredinto the surrounding cylinder 33. From this cylinder`33 it is deliveredthrough the neck 39 into the burner and from thenc into the. combustionchamber.

The prevention of arching accomplished by the chain or chains 18, thecontrol of the fuel delivery by the gates 7 and 8, and .construction andoperation of these gates and .their capability of effectually preventingleakage around the same, thel protection of the bearings in whichtherotating -shafts o erate, the breaking up ofthe fuel in t e troughand`the deliver of the saine into the preliminary mixing cy inder, and theadvantages of these various features should be appreciated withoutfurther description. 0bviousl descri ed may be varied withinconsiderable limits without departing fromthe essence of the inventionas defined in the following claims.

I claim: 1. In an apparatus of the character described, the combinationof a hopper, a pair of vrotatable vertically swinging intermediatelysupported control gates mounted beneath said hopper so that adjacentmargins of said gates overlapwhen thel gates are in closed position, andabutments at the sides of the hopper. against which the outer margins ofsaid gates close.

2.A In an apparatus for feeding powdered fuel, the combinationofahopper, a trough the structural details illustrated and beneath saidhopper, asealedcontrol gate l for controlling the delivery of fuel fromsaid hopper to said trough, a removable carrying section for said gatemeans in the hopper for preventing arching of `the fuel therein, meansin the trough foragitating and breaking up the fuel delivered theretofrom the hopper, and a feed screw for delivering said fuel from thetrough.

3. In an apparatusof vthe character de scribed, the combination of ahopper, a trough beneath said hopper, a control gate for controlling thedelivery of material from said hopper to said trough, and meansextending along the` margins of said gate for. sealing the same againstleakage, said gate including a plurality of similarly movable sectionsmounted in the hopper and overlapping one another. i r

4. In anapparatusl ofthe character described, the'combinationof a`hopper, aoontrol gate for controllingithe delivery of materialtherefrom, felt sealing .strips for preventing leakage around themargins of said gate, said gate com risingya pair of similarly rotatableover appmg se'ctlons mount# noA f ed in the hopper, and oppositelyacting stop ed beneath said hopper so that Ladjacentl margins of saidgatesoverlap when the gates are in closedl position, abutments againstwhich the outer margins of said gates close, and sealing strips .forpreventing leakage around the gates.

6. In an apparatus of Ythe character de scribed, Ithe combination of .ahopper, a rotatable control gate mounted in outboard bearings beneathsaid hopper, abutment means for limiting the closing movement of saidgate, and sealing strips for preventing leakage around the gate.

7, In an apparatus of scribed, the combination of a hopper, a pair ofrotatable ,gates mounted in outboard bearings beneath said hopper, saidgates b eing adapted to overlap when in vclosed position, abutments forlimitting vthe closing movements of said gates, and` means forpreventing leakage around the gates.

8, In an apparatus of the character described, the combination of aAhopper, and means for controlling the discharge from' said hopper, saidmeans comprising a plurality of gates rotatably mounted on horizontalaxes and adapted to overlap when in closed position.

MILTON W. 'ARROWOOD the character dec

